The radar systems are commonly provided upon vessels, for instance, for identifying the presence of the moving objects, which might be the subjects for collision. Such conventional radar systems may include a plan position indicator (hereinafter referred to as PPI), providing representation (by the marks) all objects on the screen, located over the scanned area. Further the conventional radar systems there have been developed a number of very complex radar tracking systems, using for the collision avoidance warning notification. Such radar collision preventive systems are an collision warning alarm system. For example, the collision warning target display system by U.S. Pat. No. 4,281,326 is intended for collision warning alarm actuating by a ship's whistle. This system displays (see FIG. 1) on the scope (PPI) thereof a maximum 20 and minimum 21 range (the concentric rings), defining a warning collision range (distance) for the target 6. The warning area is contained between these two concentric rings.
Also the system can be used for tow warning capability for identifying the straying of a towed barge, for example, from a predetermined tow area. The system indicates on PPI a tow warning area. The tow warning system operates to establish a tow warning area 16 extending about the two safety location 17, indicating on the PPI scope 18, as shown on FIG. 1. Vessels such as barges 19, indicated by small marks for convenience of description, are intended to be towed behind a vessel, which is marked on the PPI scope 18, and to normally remained with the two safety areas 17. If barge or towing vessel moves outside of the safety area 17 into the surrounding warning area 16, the system by U.S. Pat. No. 4,281,326 will sound an alarm to indicate that the towed vessel has either swung laterally from its normal position or has possibly broken free and is lagging too far behind the towing vessel.
Such warning target system, having the warning area contained between two concentric rings, defining by the distance between own ship and target, provides the warning alarm to the operator and has not provided the determination of the vessel (the own object) dangerous relative course zones for selection of the optimal maneuvering, for example, in the narrow fairway with a considerable quantity of the target objects. Additionally, such apparatus can not provide a visual evaluation of the dynamic processes of the non-dangerous maneuvering.
Another ship collision preventive aid apparatus by U.S. Pat. No. 4,706,090 includes a key touch panel, PPI and alarm means. As shown in the U.S. Pat. No.4,706,090, the anti-collision principles are based on the constructing of the concentric rings, determining the distance between the own ship and other moving objects respectively. Referring to this patent, the indicator (a color cathode-ray tube, hereinafter referred to as CRT) depicts the mentioned above concentric guard rings, suppression rings and object marks. The acquired ships are marked on CRT too. The alarm is adopted to be given, when the target ship crossing the guard ring of the own ship. In contrast with the U.S. Pat. No.4,706,090, described of the above, this apparatus uses the rectangular CRT and key touch control panel, excluding the mechanical control means.
Such ship collision preventive aid apparatus provides the warning alarm to the operator and has not provided the determination of the vessel dangerous relative course zones for the selection of the optimal maneuvering vector (an optimal maneuvering anti-collision speed-vector). Also such complex apparatus requires a lot of handle operations on key touch panel with a specific algorithm of the manipulation sequence, that take a lot of time for the collision preventive aid apparatus control. Additionally, such apparatus can not provide a visual evaluation of the dynamic processes of the non-dangerous maneuvering and collision avoidance simulation.
Other known methods and apparatus of prior art for collision avoidance (for example, U.S. Pat. Nos. 5,515,287; No. 4,623,966 and the others) disclose more complex processes of anti-collision maneuver selection, requiring longer time for signal processing and resulting information displaying, and more complex structures of the apparatus.